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From: Neto pr <netopr9@gmail.com>
Date: Fri, 8 Sep 2017 07:02:37 -0700
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Subject: Re: Explain Analyze - actual time in loops
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Igor Neyman <ineyman@perceptron.com>,
	"pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
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Thanks for reply Tom and Igor.

Just only more information:

I need to know the height of a B-tree index (level of the leaf node
farthest from the root).

I tried to find this data in PG_INDEXES and PG_CLASS views, but I did not
find it.
Does anyone know if Postgresql stores this information, referring to the
height of the index tree?

Regards


2017-09-08 6:44 GMT-07:00 Tom Lane <tgl@sss.pgh.pa.us>:

> Neto pr <netopr9@gmail.com> writes:
> > After analyzing, I saw that in some places of the plan, it is being used
> > Parallelism. Does this explain why the final value spent (in minutes) to
> go
> > through the index (184 minutes) is greater than the total query time (66
> > minutes)?
>
> I was just about to ask you about that.  If this is under a Gather node,
> I believe that the numbers include time expended in all processes.
> So if you had three or more workers these results would make sense.
>
>                         regards, tom lane
>

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<div dir=3D"ltr"><div>Thanks for reply Tom and Igor.<br><br></div>Just only=
 more information:<br><br>I need to know the height of a B-tree index (leve=
l of the leaf node farthest from the root).<br><br>I tried to find this dat=
a in PG_INDEXES and PG_CLASS views, but I did not find it.<br>Does anyone k=
now if Postgresql stores this information, referring to the height of the i=
ndex tree?<br><br>Regards<br><br></div><div class=3D"gmail_extra"><br><div =
class=3D"gmail_quote">2017-09-08 6:44 GMT-07:00 Tom Lane <span dir=3D"ltr">=
&lt;<a href=3D"mailto:tgl@sss.pgh.pa.us" target=3D"_blank">tgl@sss.pgh.pa.u=
s</a>&gt;</span>:<br><blockquote class=3D"gmail_quote" style=3D"margin:0 0 =
0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class=3D"">Neto p=
r &lt;<a href=3D"mailto:netopr9@gmail.com">netopr9@gmail.com</a>&gt; writes=
:<br>
&gt; After analyzing, I saw that in some places of the plan, it is being us=
ed<br>
&gt; Parallelism. Does this explain why the final value spent (in minutes) =
to go<br>
&gt; through the index (184 minutes) is greater than the total query time (=
66<br>
&gt; minutes)?<br>
<br>
</span>I was just about to ask you about that.=C2=A0 If this is under a Gat=
her node,<br>
I believe that the numbers include time expended in all processes.<br>
So if you had three or more workers these results would make sense.<br>
<br>
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 regards, tom lane<br>
</blockquote></div><br></div>

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